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Frustrated! heating large cuff evenly


#1

Had ‘one of those days’ in the studio yesterday! I know it’s a basic
problem, but I can’t seem to win. Ugh. I’m soldering a fairly large
cuff… About 2"x6", and just can’t seem to get it heated evenly
enough to make a pre-tinned overlay of lighter metal solder
completely. I’ve already fought through attaching the bezel, and the
overlay, but needed to go back in to get a couple of corners to sit
down… then disaster. My overheated (?) piece broke. Should have
taken that ‘brain break’ from it! Frustrated with the prolonged
heating, I stupidly lost patience and picked it up with tweezers to
get some heat underneath, and that side fractured right off. Now I
have to either toss it or fix it. I was going to put a strip of
tinned 28ga behind the piece for extra support under my new ‘seam’,
but is the sterling ruined now? And I still have the same problem of
getting it all to temp, especially since I was going to put a heat
sink on top of the bezel to protect it now.

I had tried a few setups, but had arrived at raising the piece up on
a honeycomb block (with holes in it). I set that on top of the
heated charcoal block I had been trying with, in attempt to get some
heat under the heavier gauge metal of the cuff. And I have more soft
firebricks set in a wall behind it all to reflect heat. My torch is
a Swiss, lots of heat I think.

Sorry, I know that this is probably a basic problem, but I couldn’t
find much in the archives aside from building a ‘furnace’ out of a
coffee can and stove pipe. Couldn’t quite follow the instructions
for that excellent idea though.

Can someone help me out, I would love to make more cuffs like this
one.

Thanks!
Linda Meraw
… In the heart of the beautiful Okanagan valley, BC.


#2

Linda,

I just had to respond to your message. I have a sign in my shop that
says Stop before you get hurt. It seems people always gets hurt (or
ruins pieces) when they get tired or upset because something doesn’t
go just right. I cut the tips of my fingers with a lapidary saw
because I only had a little bit more to go and it seemed the piece
was not cutting right. I was just not holding it right because I was
tired. I had been fighting it for a while. Luckily I didn’t lose my
fingertips but I put that sign up and have safety signs over all
pieces of equipment.


#3

One could help more if you could post some pictures of it somewhere.
You say, tinning? thats really a lead/tin solder technique and
shouldnt be used on sterling silver.

also you dont say what size is your torch? burner head diameter? A
1in dia propane only will be plenty for a cuff 2in by 6in.

OR

think of a way to make it entirely cold,ie only by hammering. Ask the
question? how can I make this all cold? Ive developed products that
dont need soldering work fine, and sell well.


#4
and just can't seem to get it heated evenly enough to make a
pre-tinned overlay of lighter metal solder completely. 

Temperature is not the problem here. The problem is fitting. In any
overlay work upper pieces must fit without any gaps. Tinning lighter
part prior to soldering is not ideal in this situation. Both pieces
should fit, so if drop of water is introduced between them and
assembly is turned over, the lighter piece should hold without any
other means. Once fit is achieved, solder it by using few small
paillons of solder. It does not take much solder to obtain good
joint. Heat only large part allowing heat transfer to bring smaller
part to the temperature.

Leonid Surpin
www.studioarete.com


#5

Linda- When I solder large silver or copper things I use a pumice
pot. I have an old cast iron pot that I fill with pumice lumps. It
sits on a rotating trivet so that I can rotate the pot to spread the
heat evenly. It really helps get large things heated. I learned to
use one when I was a liturgical silversmith.

Have fun and make lots of jewelry.
Jo Haemer
www.timothywgreen.com


#6
My torch is a Swiss, lots of heat I think. 

You need a bigger tip or torch if you are going to heat the whole
thing at once.

James Binnion
James Binnion Metal Arts


#7
I put that sign up and have safety signs over all pieces of
equipment. 

Just don’t clean off the blood. Every time you begin working again
with that tool or at that station you’ll see your dried blood and
remember.


#8

Linda,

It sure sounds like you’re not getting enough generalized heat on the
cuff you’re trying to solder. In our studio, we use a large,
heavy-duty soldering screen, long enough to lay your cuff bracelet
on flat. We use a large tip on an acetylene/air torch to heat beneath
the cuff in a large circular motion to evenly heat the cuff. For
really large pieces, we have to use a second identical torch to get
the cuff hot enough for the solder to flow.

I think a soldering block with holes is going to do more to prevent
heat getting to your piece than not. Try direct heating from
beneath.

We have a Swiss torch in our studio, which is powered by propane and
oxygen. They do make a “casting tip” for that torch, which we have,
that looks like an old fashioned shower head fixture from an old
hotel. That tip might be what you need to heat that large piece of
metal.

Good luck with soldering large pieces of 28 ga. metal to your cuff.
I find that soldering that thin of sheet in large sections causes
major warping with the soldering process, and nearly impossible to
keep flat.

Jay Whaley


#9

Hi Linda-

I did a heavy silver cuff and used wire mesh on a tripod. Heating it
with Acetylene/Oxygen. I had the opposite condition of it heating
very quickly. Coated the whole thing in hard solder paste flux…
Worked. Mostly because I could get to all sides & ample heat.

James


#10

Hey Linda,

It takes a tremendous amount of heat on a piece like that to get the
pre-tinned pieces to flow completely. How thick is your base piece? I
would use a tripod with a woven iron screen on the top. Dip your
pieces with boric acid/alcohol or use pripp’s to help minimize
firescale. I use a white paste flux as well, and apply as the base
piece begins to warm, then position your tinned pieces on top. At
this point, you need to be using a huge flame from underneath, and
keep it moving to bring the entire piece up to temperature. When the
paste flux becomes clear, and the piece is near soldering temps, hold
your flame closer at one end, and when the solder begins to flow,
move the flame evenly between the top and the bottom pieces along the
length of the cuff. The goal is to use a sufficient amount of heat
that the solder flows completely and evenly along the length. If you
have gaps in the metal, you can use soldering tweezers to push down
gently on those little bits, or a solder pick to encourage an even
flow. It’s way more difficult to get seams complete on a second or
third try due to firescale, burnt out flux globs left, excessive
gaps, not to mention the need for higher temps to re-melt previously
melted solder. You may find that another person with a second torch
is necessary to keep enough heat underneath while you apply heat from
the top. I’m not familiar with the Swiss torch, I have used a #7 or a
brazing tip on a little torch, acetylene and oxy set-up, or an
old-fashioned Hoke torch, large tip, with propane and oxy.

Hope this helps,
Melissa Veres, engraver


#11

I actually get a helper when I am heating a large piece so it can be
heated on the front and back.

Barbara Blaschke


#12

Thank you everyone for the great advice. Got to love Ganoksin, I am
so fortunate to have advice from such professionals.

Further to my question though, I’m wondering if the cuff is ruined
now. It has taken alot of heat, and since the piece broke when I
lifted it, are the ‘crystals’ in the metal now such that even if I
repair the piece, will it now be too brittle to form into a cuff?

Much appreciated,
Linda


#13

Hi Linda, After a long learning curve I have finally come up with a
system that works for me.

First off, I use Argentium silver which is very helpful for its
fusing properties. Here is my technique…

18g silver for the cuff26g silver for the flowers/animals/what
ever… After forming all my pieces I to “tin” the back of the
pieces with Med solder I then flux everything again, heat the fluxed
pcs just enough to get rid of white flux (I dont want the pcs to
float when the flux settles down) place the pcs on the cuff (which is
located on a screen between 2 upended soldering bricks (so it is
high) I then heat the bottom of the cuff until the flux turns
clear/brownish and I can see the metal is heating upI then quickly
go to the top and focus on and area. this part goes fairly quick. I
heat it to the point of just before fusing (sometimes it does fuse.
(this really comes with experience as it will go “to far” in an
instant.)I then move on to the next closest area and do the same.

I have a soldering pic in hand and if a pc is raised up, gently
press down while heating (another very tricky area, as argentium
will break if you do not do this at the absolute right time.when It
is done and cooled, I check all joins.

if there is a partial flower sticking up I will take a small wooden
dowel (cut small pcs from a long one from Lowes) and with a chasing
hammer,gently hammer the piece down to the cuff.

trying not to mess up the shape of the flower. I then heat the whole
thing again from the bottom and quickly focus on the top that I am re
doing. I may have added another bit of easy solder or just heated to
the point of fusing.After cleaning the piece I then shape the cuff on
the mandrel, trying to avoid my flowers. At times something else will
pop up (leaf, petal etc) at this point I finish the forming and go
back to my wooden dowel technique to press down the leaf. I then use
Super easy solder to attach the piece without having to heat the
whole cuff again… And thats basically it!

It may not be a traditional technique but it works for me. hope
something in here will help you too!

Best, gail
gailwilliamsjewelry.com